4. In the block-spring arrangement of Fig. 4, the block’s mass

is 4 kg and the spring constant is 500 Nm. The block is

released from position xi=0.300m. What are (a) the block’s

speed at x=0, (b) the work done by the spring when the block

reaches  x=0 , (c) the instantaneous power due to the spring at the

release point xi, (d) the instantaneous power at x=0, and (e) the

block’s position when the power is maximum?